Thanks, that makes sense as we have had a lot of rain over the past few days. I'll cover the tree if it rains again. Should I just leave it or try to brush off?That looks like either slime mold or algae. Either way, it's an indicator that the soil is far too consistently wet--That's not great for pines...
I think your issues could be deeper than covering the soil. It's a symptom of a larger problem from what I can see in the photo. The soil itself looks very wet and dense. When's the last repotting for this tree? You can let it dry a bit, the algae will dry up, but will come back the next time you water or it rains. ...Thanks, that makes sense as we have had a lot of rain over the past few days. I'll cover the tree if it rains again. Should I just leave it or try to brush off?
Thanks again
unfortunately, I'm not a "pine person. "I think it could probably do with a re-potting. I bought the tree around two years ago and I'm not sure on the last potting from when I got the tree. I did want to get a larger pot for the tree anyway but my plan was to wait until Autumn to re-pot as I understood this was a better time to re-pot japanese white pines. But do you think I should do this sooner rather than later?
Thanks Sorce - I will do as you suggest! Looking forward to that full moonDon't Repot!
Just scrape it and watch your water.
Do a post summer Solstice Repot at a full moon.
"Fall" can be late.
Sorce
Thanks Sorce - I will do as you suggest! Looking forward to that full moon![]()
I'm based in the UK, where I have read some say repotting can be done in early spring (which I have missed), or early Autumn. However most seem to be saying its better to wait til early Spring just as the buds appear - which is a long way off!Of because of location.
..
What is your location?
Sorce
in the UK,
Yes please , should be London, UKI believe I remember this answered before, apologies, do you want me to shtik it in your profile?
I feel Summer is safer than Spring for you.
Sorce
Thanks Leo, that is very helpful. I just tried this approach with a thin chopstick. There were a few places where the chopstick went through relatively easier but others where the soil/small stones are very compact - is it ok to force through?One might try taking a bamboo skewer, or a thin chopstick, and poke holes every centimeter, all the way through the root ball to the bottom of the pot. This will help aerate the soil if it is compacting. I agree with RockM's diagnosis, an algae crust or slime mold, that is indicative of loss of air movement into the soil. I don't think the slime is a precursor to moss. While vaguely similar there is a different look to the sexual phase of moss. (the thallus phase). The black slime looks to me like Nostoc, a blue-green algae that is the harbinger of deteriorating conditions in a bonsai pot.
But the activity of aerating the soil will buy you as much as a year or so of time before repotting, if repeated every 3 or 4 months. So you can limp this tree along to a "safe window of time" for repotting.